The Indian Medical Association (IMA) declared a public health emergency in the city on Tuesday as the city's air quality rating climbed above the highest levels on the index. People have been advised to avoid outdoor activities and keep children indoors to avoid the “severely harmful” air.

The education minister confirmed elementary schools will be closed on Wednesday, saying an extension of the order is possible.

The problem is expected to linger for some time.

The Doctors Association requested that the Airtel Delhi Half Marathon, scheduled for November 19, be cancelled, according to local media reports.

Flight schedules have also been changed due to low visibility. On Tuesday, more than 20 flights were delayed and at least four were rerouted.

The Air Quality Index (AQI) in Delhi is currently 316, well above the threshold for “severely polluted,” according to officials. AQI scores range from excellent and good at 0-50 and 51-100, lightly polluted and moderately polluted at 101-150 and 151-200 and heavily and severely polluted at 201-300 and 300+.

The air quality in the Punjab region is even worse than Delhi, with an index of 462. Many believe stubble burning -- the practice of burning fields to clear them for planting -- has contributed to the extreme pollution there and elsewhere.

Despite restrictions on stubble burning in Punjab, many do not comply with the new regulations. The resulting smoke is creating problems not only for that region, but also for adjacent provinces in both India and Pakistan.

Imran Hussain, minister of food and civil supplies, environment, forests and election in Dehli, said he has asked Punjab officials to curb the burns to control air pollution in Delhi. But no action has been taken.

Punjab officials deny the effect on Delhi's air quality, saying stubble burning has been reduced by thirty percent since Punjab banned crop burning in 2013.